The present invention relates to an anti-abrasion pipe fitting for high-speed particle-laden flow.
Generally, a material feeding pipe is used for feeding a certain powder material such as fly ash, bottom ash, etc. in an industrial facility such as a fossils electric power plant, a steel fabrication factory, a cement fabrication factory, and the like. In these cases, as a feeding method, a wet feeding method is known for mixing water with a powder material in a slurry form and feeding the mixed slurry. As another feeding method, a dry feeding method is known for feeding a powder material using a mechanical force or pneumatic pressure.
In the wet feed method, since a certain material is fed based on its weight, a small amount of force is used, and a small abrasion occurs at an inner wall of a curved coupling pipe, so that its life span is increased. However, after the material is fed, the slurry is compressed by a filter press, etc. and is dehydrated. Namely, in this case, a process is additionally required, so that a related facility becomes bulky, and the area for installing the bulky system is increased. In particular, a polluted water containing heavy metals may be produced, so that an environment may be polluted during a cooling process.
In addition, in the dry feeding method, since a post-process is not required, the system may be simplified, and the fabrication cost is minimized. However, lots of power is required for feeding powder materials, and an abrasion is increased at an inner wall of a coupling pipe, so that a maintenance cost is increased.
In the case that a powder material containing a burned lime is mixed with water, the volume of the burned lime is sharply increased for thereby resulting in an explosion of the burned lime. Therefore, in this case, the dry feed method is generally used.
The conventional curved coupling pipe for a high speed powder material feed pipe will be explained.
FIG. 23 is a view illustrating a conventional 90 elbow 100 which includes an upper side straight portion 101, a lower side straight portion 102 which is perpendicular to the upper side straight portion 101, and a flow direction changing portion 103 connecting the upper side straight portion 101 and the lower side straight portion 102.
The upper side straight portion 101, the lower side straight portion 102, and the flow direction changing portion 103 have the same diameter. The center line C of the upper side straight portion 101 and the lower side straight portion 102 has a radius curvature of a xc2xc circle.
The movement of the powder material in the conventional elbow 100 will be explained. At the center portion, the flow speed of the upper side straight portion 101 is fast, and is gradually decreased in the direction of the pipe inner wall. At the flow direction changing portion 103, the flow speed at the outer side curved portion 103a is fast, and the flow speed at the inner side curved portion 103b is slow, so that a high speed zone H is formed at an inner wall side of the outer side curved portion 103a, and a low speed zone L is formed at an inner wall side of the inner side curved portion 103b. At the lower side straight portion 102, the flow speed is fast at the center portion, and is decreased in the direction of the pipe inner wall side, so that the flowing amount and flow speed at the upper side straight portion 101 and the lower side straight portion 102 are same.
Here, assuming that the flow speed of the powder material at the upper side straight portion 101 is 35 m/sec(2100 m/min), the flow speed at the high speed zone H is 45 m/sec(2700/min), and the flow speed at the low speed zone L is 15xcx9c25 m/sec(900xcx9c1500/min).
Therefore, in the outer side curved portion 103a of the flow direction changing portion 103 of the elbow 100 having the high speed zone H, a collision of the powder materials which are linearly moved from the upper side straight portion 101 occurs. In addition, a great abrasion occurs due to a friction with the fed powder material and a decreased anti-abrasion due to a heat generated at an inner wall of the pipe.
The anti-abrasion occurs due to the heat generation at the inner wall of the pipe. In detail, the temperature of the powder material reaches about 80 C. When the above-described powder materials are fed, the inner wall of the powder material feed pipe is heated. In particular, the heat is generated due to the temperature of the powder material and a friction with the powder materials at the outer side curved portion 103a of the flow direction changing portion 103, so that the anti-abrasion characteristic of the pipe wall is decreased.
Next, the abrasion due to the collision and friction of the powder materials will be explained. Since a high speed zone H is formed at the outer side curved portion 103a of the flow direction changing portion 103, an abrasion due to a collision with the powder materials occurs.
Here, the degree that the flow speed and pressure at the high speed zone H of the powder materials fed in the high speed powder material feed pipe affects the abrasion will be compared with those of a grinding process.
The polishing speed(the sum of the circular speed of the grinding wheel and the relative moving speed of the grinding wheel and an object) of the grinding wheel used for the grinding process is 2200xcx9c3400 m/min, and the grinding pressure is 0.50xcx9c0.7 kg/cm2, and the feeding amount of one time is maximum 5_ when the grinding process is performed using a cooling water. As a result, the MOS hardness of the powder material is 5.5xcx9c6.5. Assuming that the flow speed at the upper side straight portion 101 is 2100 m/min, since the flow speed at the high speed zone H is 2700 m/min, an abrasion is increased due to a collision and friction of the powder materials at the inner wall of the pipe at the high speed zone H.
In the case of the dry feed method, since water is not provided, the abrasion is increased compared to the grinding process in which a cooling water is provided.
In addition, since the abrasion at the outer side curved portion 103a of the flow direction changing portion 103 does not uniformly occur. Namely, as shown in FIG. 23, an erosion zone EZ is formed at the portion in which the abrasion occurs at an initial stage. The abrasion is performed at this portion as faster as the other portions by 2.06 times.
The frequent maintenance of the powder material feed pipe is required due to the above-described abrasion. In order to perform the maintenance, since the operation of the system is stopped, much economic loss occurs.
As shown in FIG. 24, the 45 elbow includes a lower side straight portion 202 which is formed at an angle of 45 with respect to the upper side straight portion 201 and the upper side straight portion 201, and a flow direction changing portion 203 connecting the upper side straight portion 201 and the lower side straight portion 202.
The above-described 45 elbow 200 includes a certain flow direction changing angle between the upper side straight portion 201 and the lower side straight portion 202 which is different from the 90 elbow 100 and includes a high speed zone H formed at the outer side curved portion 203a of the flow direction changing portion 203 and a low speed zone L formed at the inner side curved portion 203b. The abrasion is sharply increased at the high speed zone H by the above-described reasons.
As shown in FIG. 25, the T-shaped coupling pipe 300 includes a first upper side straight portion 301, a lower side straight portion 303 formed on the same axis as the first upper side straight portion 301, and a second upper side straight portion 302 which is perpendicular to the first upper side straight portions 301 and 303.
An upper side flow direction changing portion 304 is formed between the first upper side straight portion 301 and the second upper side straight portion 302. A lower side flow direction changing portion 305 is formed between the second upper side straight portion 302 and the lower side straight portion 303. A connection portion 306 is formed between the first upper side straight portion 302 and the lower side straight portion 303.
In the case of the T-shaped coupling pipe 300, an abrasion occurs at the lower side flow direction changing portion 305 due to a collision with the powder material which is fed at a high speed from the first upper side straight portion 301, and an abrasion occurs at the first upper side straight portion 301 and the lower side straight portion 303 by a collision with the powder materials which are fed at a high sped from the second upper side straight portion 302, so that the life span of the system is decreased.
As shown in FIG. 26, in the case of the Y-shaped coupling pipe 400, there are provided a first upper side straight portion 401, a lower side straight portion formed on the same axis as the first upper side straight portion 401, and a second upper side straight pipe 402 connected at an angle of 45 with respect to the first upper side straight portion 401 and the lower side straight portion 403.
An upper side flow direction changing portion 404 is formed between the first upper side straight portion 401 and the second upper side straight portion 402. A lower side flow direction changing portion 405 is formed between the second upper side straight portion 402 and the lower side straight portion 403. A connection portion 406 is formed between the first upper side straight portion 401 and the lower side straight portion 403.
The above-described Y-shaped coupling pipe 400 includes a certain connection angle of the second upper side straight portion 402 with respect to the first upper side straight portion 401 and the lower side straight portion 403 which is different compared to the above-described T-shaped coupling pipe 300. An abrasion occurs at the lower side flow direction changing portion 405 due to a collision with the powder materials which are fed at a high speed from the first upper side straight portion 401. An abrasion occurs at the first upper side straight portion 401 and the connection portion 406 of the lower side straight portion 403 due to a collision with the powder materials which are fed at a high speed from the second upper side straight portion 402, so that the life span of the system is decreased.
As shown in FIGS. 27 through 30, a protection film F formed of an anti-abrasive material, such as, an alumina, basalt, cemented carbide, etc. is lined on an inner wall of the pipe for thereby decreasing the abrasion.
However, even when the protection film F is lined, a high speed zone H is formed at a flow direction changing portion, etc, so that it is impossible to basically prevent the abrasion due to a collision with the powder materials. Since an expensive anti-abrasive material which is used for the protection film F is used, the fabrication cost is increased, and it is impossible to obtain a satisfactory effect due to a limit in the anti-abrasive characteristic.
In the case that particles of Al2O3, SiO2, etc. having a MOS hardness of 5.5xcx9c6.5 are fed into the pipe of a diameter of 100xcx9c400 mm at a speed of 8xcx9c45 m/sec, the flow speed at a portion in which the flow direction is changed is increased by more than 1.2xcx9c1.5 times compared to the flow speed in the straight pipe. Therefore, even when the protection film F formed of an anti-abrasive material is lined, the protection film F is worn and loses a function as a protection film, so that it is impossible to actually use the protection film F.
In the conventional art, the curvature of the flow direction changing portion is designed to have a certain curvature which is 10 times the standard curvature radius, so that the flow direction changing portion becomes nearly straight for thereby effectively decreasing the abrasion at the flow direction changing portion.
However, in the above-described conventional curved coupling pipe, since the length of the pipe is increased, and the occupying area of the pipe is increased, it is impossible to effectively use the space of the system.
In the conventional curved coupling pipe, a pocket is formed at the outer side curved portion of the flow direction changing portion or at a portion in which a collision occurs, so that the powder materials collide with the powders at the pocket for thereby changing the flow direction and decreasing the abrasion.
However, at the above-described conventional fittings, as time is elapsed, the amount of the powders gathered at the pocket is increased, so that an effective standard pipe range is decreased for thereby causing a flow loss.
In the conventional art, the thickness of the standard pipe wall at the portion in which the powder collides with an outer curved portion of the flow direction changing is 10 times the standard pipe wall thickness. so that even when an abrasion occurs, it is possible to use the curved coupling pipe for long time.
However, in the above-described fittings, the cost of the materials is expensive, and as the depth of the erosion zone EZ is increased, a flow problem occurs.
The pipes which are capable of feeding the powders based on the pneumatic pressure and a pressurized gas/liquid have the above-described problems. In addition, the curved coupling pipe used for feeding gas or fluid at a high speed has the above-described problems.
Accordingly, it is an object of the present invention to provide an anti-abrasion pipe fitting for high-speed particle-laden fluid which is capable of preventing an abrasion at a portion in which a flow direction is changed without forming a protection film formed of an anti-abrasive material at an inner wall of a pipe for thereby increasing the life span of the system.
To achieve the above objects, there is provided an anti-abrasion pipe fitting for high-speed particle-laden flow according to the present invention which includes a plurality of flow fields such as a vortex flow field formed at a flow direction changing portion during a fluid feed by expanding an outer side curved portion and inner side curved portion of the flow direction changing portion to the outside of a standard flow range in an elbow shaped curved coupling pipe formed of an upper side straight portion, a lower side straight portion perpendicular to the upper side straight portion, and a flow direction changing portion formed between the upper side straight portion and the lower side straight portion.
An upper side curved portion is formed between the upper side straight portion and the flow direction changing portion, and a lower side curved portion is formed between the lower side straight portion and the flow direction changing portion.
To achieve the above objects, there is provided an anti-abrasion pipe fitting for high-speed particle-laden flow which includes a plurality of flow fields such as a vortex flow field formed at the flow direction changing portion during a fluid feed by forming the upper side flow direction changing portion based on the standard flow range and expanding the lower side flow direction changing portion to the outside of the standard flow range, wherein a T-shaped curved coupling pipe includes a first upper side straight portion, a lower side straight portion extended on the same axis with respect to the upper side straight portion, a second upper side straight portion formed at a certain angle with respect to the first upper side straight portion and lower side straight portion, an upper side flow direction changing portion formed between the first upper side straight portion and the second upper side straight portion, a lower side flow direction changing portion formed between the second upper side straight portion and the lower side straight portion, and a connection portion connecting the first upper side straight portion and the lower side straight portion.
A curved recess is formed on an inner surface of the portion connecting the first upper side straight portion and the lower side connection portion for thereby forming a plurality of flow fields such as a vortex flow field at the recess during a fluid feed.
To achieve the above objects, there is provided an anti-abrasion pipe fitting for high-speed particle-laden flow which includes a plurality of flow fields such as a vortex flow field formed at the flow direction changing portion during a fluid feed by forming the upper side flow direction changing portion based on the standard flow range and expanding the lower side flow direction changing portion to the outside of the standard flow range, wherein a Y-shaped curved coupling pipe includes a first upper side straight portion, a lower side straight portion extended on the same axis with respect to the upper side straight portion, a second upper side straight portion formed at a certain angle below 90 with respect to the first upper side straight portion and lower side straight portion, an upper side flow direction changing portion formed between the first upper side straight portion and the second upper side straight portion, a lower side flow direction changing portion formed between the second upper side straight portion and the lower side straight portion, and a connection portion connecting the first upper side straight portion and the lower side straight portion.
A curved recess is formed on an inner surface of the portion connecting the first upper side straight portion and the lower side connection portion, for thereby forming a vortex flow field during a fluid feed by expanding the diameter of the pipe.
Additional advantages, objects and features of the invention will become more apparent from the description which follows.